The ABC's of germanium

THE FIELD OF the semiconductors embraces that broad category of solid materials whose characteristics lie between those of the conductors and the insulators. The mechanisms governing their behavior are not well known. They can be broadly divided into two categories, the compounds and the elements. Among the elemental semiconductors exhibiting rectifying properties are silicon, gray tin, and germanium. Of these, germanium has been studied most intensively because its physical properties are best suited for industrial application, although silicon crystals were in use long before the rectifying properties of germanium were recognized. Thus, the following discussion presents, in engineering language but in a simplified manner, some of the mechanisms governing the behavior of germanium. However, it must be understood that because of the complexity of the subject and the lack of understanding of many of the phenomena, the explanations given are, in many cases, not rigorous and in the light of future developments may even be erroneous. However, they provide a working understanding of the behavior and limitations of germanium as applied to industrial devices, and permit following future developments of the devices with some comprehension.